Consolidated Statements of Shareholders' Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Paid-In-Surplus [Member]	Retained Earnings [Member]	Unrealized Appreciation of Investments Including Unrealized Other-Than-Temporary Impairment Losses [Member]	Postretirement Benefit Costs Not Yet Recognized in Net Income [Member]	Foreign Currency Translation Gains (Losses) [Member]	Accumulated Other Comprehensive Income [Member]	Treasury Stock, at Cost [Member]
Balance, Beginning of Year at Dec. 31, 2013			$ 171	$ 21,902	$ 1,225	$ (253)	$ 63		$ (7,383)
Net Income	$ 1,542			1,542
Repurchase of Shares									(1,209)
Changes Related to Stock-Based Employee Compensation (includes tax benefit of $4 and $16)			(20)
Change During Period, Net of Tax	403				427	17	(41)
Dividends Declared (per share $1.71 and $1.50)				(365)
Shares Issued Under Stock-Based Employee Compensation Plans									58
Balance, End of Period at Sep. 30, 2014	16,506	$ 372	151	23,079	1,652	(236)	22	$ 1,438	(8,534)
Balance, Beginning of Year at Dec. 31, 2014	16,296		171	23,520	1,753	(589)	(54)		(8,877)
Net Income	1,470			1,470
Repurchase of Shares									(604)
Changes Related to Stock-Based Employee Compensation (includes tax benefit of $4 and $16)			8
Change During Period, Net of Tax	(449)				(285)	35	(199)
Dividends Declared (per share $1.71 and $1.50)				(394)
Shares Issued Under Stock-Based Employee Compensation Plans									44
Balance, End of Period at Sep. 30, 2015	$ 16,371	$ 372	$ 179	$ 24,596	$ 1,468	$ (554)	$ (253)	$ 661	$ (9,437)